Table of Contents:

Definition and Overview

1. Gatekeeper Environment

2. Mandatory Features

3. Optional Features

4. Practical Applications

5. Current Role

6. Future

Self-Test

Glossary

PDF of this tutorial

ACF
admissions confirm message

API
application programming interfaces

ARJ
admissions reject message

ARQ
admissions request message

H.225.0
an ITU–T recommendation that specifies call-signaling protocols and media stream packetization for packet-based multimedia communication systems.

H.245
an ITU–T recommendation that defines the control protocol for multimedia communication

H.323
an umbrella recommendation from the ITU–T that specifies real-time multimedia communications over protocol-compliant networks

HTTP
hypertext transfer protocol

ILS
Internet locator service

IP
Internet protocol

ISP
Internet service provider

IT
information technology

ITU–T
International Telecommunications Union–Telecommunications Standardization Sector

IVR
interactive voice response

MCU
multipoint conferencing unit

MIS
management information system

PBX
private branch exchange

PSTN
public switched telephone network

QoS
quality of service

RAS
registration, admission, and status

SNMP
signaling network management protocol

URL
universal resource locator